Genelle Renee Conway-Allen, 13, of Suisun City, in a photo taken just before she was last seen Jan. 31, 2013. Her body was found the next day in a park in Fairfield.

Photo: Courtesy Of Fairfield Police, Fairfield Police

Genelle Renee Conway-Allen, 13, of Suisun City, in a photo taken...

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Genelle Renee Conway-Allen, 13, of Suisun City, who was last seen Jan. 31, 2013. Her body was found the next day in a park in Fairfield.

Photo: Courtesy Of Fairfield Police, Fairfield Police

Genelle Renee Conway-Allen, 13, of Suisun City, who was last seen...

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Genelle Renee Conway-Allen, 13, of Suisun City, who was last seen Jan. 31, 2013. Her body was found the next day in a park in Fairfield.

Photo: Courtesy Of Fairfield Police, Fairfield Police

Genelle Renee Conway-Allen, 13, of Suisun City, who was last seen...

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Parents and children from the nearby Sheldon Elementary school pray for the 13-year-old Green Valley Middle School student Genelle Renee Conway-Allen at her memorial in Allan Witt Park in Fairfield, Calif., on Monday, February 4, 2013.

Photo: Liz Hafalia, The Chronicle

Parents and children from the nearby Sheldon Elementary school pray...

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Eric May, a homeless man, said he found the body of 13-year-old Green Valley Middle School student Genelle Renee Conway-Allen at Allan Witt Park in Fairfield, Calif., before alerting passing police.

Photo: Liz Hafalia, The Chronicle

Eric May, a homeless man, said he found the body of 13-year-old...

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Looking at messages at the memorial for 13-year-old Green Valley Middle School student Genelle Renee Conway-Allen on Monday, February 4, who was found dead at Allan Witt Park in Fairfield, Calif.

Photo: Liz Hafalia, The Chronicle

Looking at messages at the memorial for 13-year-old Green Valley...

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The playground was under investigation during the weekend as it remains empty on Monday, February 4, after 13-year-old Green Valley Middle School student, identified by friends as Genelle Renee Conway-Allen, was found dead at Allan Witt Park in Fairfield, Calif.

Photo: Liz Hafalia, The Chronicle

The playground was under investigation during the weekend as it...

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Cheryl Parrish (left) and her aunt Roshawn Forrest (right) holding Coco from Fairfiled on Monday, February 4, at a memorial for 13-year-old Green Valley Middle School student Genelle Renee Conway-Allen who was found dead and naked at Allan Witt Park in Fairfield, Calif.

Photo: Liz Hafalia, The Chronicle

Cheryl Parrish (left) and her aunt Roshawn Forrest (right) holding...

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Anayah Hyde (left) and Anastasia Keola visit a makeshift memorial at Allan Witt Park in Fairfield, Calif. on Saturday, Feb. 2, 2013, one day after Genelle Renee Conway-Allen's body was discovered in the park Friday morning.

(02-05) 17:55 PST FAIRFIELD -- Fairfield police seeking leads into the killing of a 13-year-old girl released a surveillance photograph taken of the teenager just minutes before she disappeared and hours before her body was found in a city park.

Police hope the photo of Genelle Conway-Allen, taken Thursday afternoon at the intersection of East Tabor Avenue and Grande Circle in east Fairfield, will jog the memory of someone who may be able to help police identify a suspect.

Genelle was wearing a gray sweater, skinny-legged blue jeans and a pink backpack. The spot where the picture was taken is near the border with Suisun City, the town where Genelle lived.

On Monday, the girl's relatives said police had told them she was last seen after she got off the bus from Green Valley Middle School, where she was a seventh-grader.

Sgt. Matthew Bloesch said witnesses have also reported seeing Genelle walking along Railroad Avenue in Suisun City, a few blocks from where the photo was snapped.

Her naked body was found early Friday about 4 miles away in Allan Witt Park in Fairfield. An autopsy was conducted, but police have not said if they know how she was killed.

On Monday, relatives described Genelle's childhood as difficult and said she had shuttled among foster care homes with her 10-year-old brother.

Relatives said Genelle's father had not been involved in her life and that she commonly used her mother's last name, Conway.

On Tuesday, police said the name on Genelle's birth certificate includes her father's surname, Allen.

A candlelight vigil for Genelle is scheduled for 6:30 p.m. Friday at Allan Witt Park.

Anyone who might have information about the crime is asked to call the Fairfield police tip line at (707) 428-7345. Callers can remain anonymous.